Allen Wayne Porter, left, and Michael Anthony Green are both inmates who will be likely be exonerated after a group established by Texas' Harris County District Attorney's office reexamined their cases and found that they were both wrongly convicted.

Courtesy Texas Department of Corrections

After 27 years behind bars, Michael Anthony Green is slated for release from a Texas prison today after an investigation revealed that he was innocent of a 1983 aggravated sexual assault for which he was sentenced to 75 years in prison.

He'll be the second man wrongly-convicted of rape to be freed from a Texas jail in the past week.

Green and Allen Wayne Porter, who was released on bond last Friday after it was determined that he was not one of the three men who invaded a southwest Houston apartment in 1990 and raped two women, served a combined 46 years before a group comprised of local lawyers and investigators reviewed their cases and unearthed new facts.

In both cases, the men wrote letters from their cells for years to various lawyers and courts proclaiming their innocence. But they had never been able to get anyone to pay attention.

"In Green's case, this lingered for many, many years until the section developed," said Green's attorney Bob Wicoff, adding that Green had written letters since he was imprisoned at age 18 and had "clamored about the injustice" for years.

Porter's attorney, Casey Garrett, said that it wasn't until the Post Conviction Review Section took up her client's case that he actually began to be hopeful that he'd one day be free.

"I don't know if he ever believed he was going to get out," said Garrett. "After all these years and all of his letters falling on deaf ears for so long, he never really believed this would happen."

"[Last year] he became cautiously hopeful and he indicated to me that this was the first time he felt hopeful that something might be happening," she said.

"For 20 years he's been writing letters to people saying he's innocent and pleading with them to review his case," said Garrett. "And then in 2009 he wrote just another letter to the District Attorney's office and by then this team had been developed."

Garrett says Porter, who served 19 years of a life sentence, has expressed his gratitude to the D.A.'s office since his release last week and knows that their hard work was essential to his exoneration.

Texas' Post Conviction Review Section Proves Two Wrongful Convictions

Porter was arrested while attending the trial for his nephew, Jimmy Hatton, who had been charged as one of the assailants in the 1990 home invasion.

According to Garrett, one of the victims saw Porter in the hallway outside the courtroom and told police that she recognized him as one of her attackers. Porter was arrested, charged and later convicted with the crime, sentenced to life in prison just six months later.

Even though Hatton knew at the time that Porter was innocent he was reluctant to admit to having been at the scene and knowing that Porter was not there because of his own ongoing appeals process, according to Garrett.

It wasn't until 2003, when Hatton's DNA was found on a condom left at the scene, did he finally admit that Porter had nothing to do with the crime. But at the time, even that didn't free Porter.

"When Hatton came forward it was dismissed as him trying to help his buddy," said Garrett.